In order to select or manufacture a shoe or a shoe sock liner which properly fits a foot of a customer, the angle of inward/outward inclination of the customer's foot is measured. The foot inclination angle is one of the most critical information in selecting (manufacturing) a shoe (especially, such as a custom-made shoe and a corrective shoe) or a shoe sock liner (especially, such as a corrective sock liner and a sock liner part). To sum up, based on the measured foot inclination angle and so on, a shoe or a shoe sock liner for correcting the inclination of a foot is selected or manufactured.
Conventionally, the angle of inclination of a human foot is measured by a specialist skillful at foot measurement (such as experts including orthopedist, physiotherapist, artificial-limb orthotist, shoe fitter etc.) while the foot is being examined by touch. More specifically, the upper and lower ends of a calcaneal bone when viewed from the rear of the foot are confirmed by palpation. Then, a line connecting together these two points is drawn on the skin and the angle of inclination of that line is measured (see, for example, JP 2001-104005 A (page 3, FIG. 2)).
However, the problem with the above is that measurement of the angle of inclination of a foot by palpation requires measurers with the right skills. It is difficult for an inexperienced measurer to make accurate measurement of the foot inclination angle and, besides, the level of reproducibility is low. This may arise a situation that measured inclination angles may differ with the measurer. For this reason, it has been difficult to select (manufacture) shoes (particularly, such as custom-made shoes and corrective shoes) or shoe sock liners (particularly, such as corrective sock liners and sock liner parts) which are best suited for customers.